Ubuntu Commands
Misc. Ubuntu commands.
Remove Pre-installed
If you don’t know what they are …
1
| apt purge cloud-* snapd whoopsie* unattended-upgrades ubuntu-advantage-tools
|
If not using LVM, LXC/LXD
1
| apt purge lvm2 lxd lxcfs
|
If completely rely on journald.
1
| apt purge rsyslog libestr0 libfastjson4
|
Get Version
Change Timezone
1
| dpkg-reconfigure tzdata
|
systemd-resolver
Ubuntu/Systemd use systemd-resolver for dns lookup and /etc/resolve.conf no longer show the actual upstream dns. Use following to check and change.
Show DNS Settings
Change DNS
1
2
| resolvectl dns <interface> <dns1> <dns2> ...
resolvectl dns enp0s2 8.8.8.8 8.8.4.4 1.1.1.1
|
Change Search Domain
1
2
| resolvectl domain <interface> <domain>
resolvectl domain enp0s2 johnsiu.com
|
Disable CPU mitigations
Do this at your own risk.
/etc/default/grub
1
| GRUB_CMDLINE_LINUX_DEFAULT="noibrs noibpb nopti nospectre_v2 nospectre_v1 l1tf=off nospec_store_bypass_disable no_stf_barrier mds=off mitigations=off"
|
Update GRUB
1
2
3
| update-grub
grub-install <boot disk>
grub-install /dev/sda
|
Update Initramfs
This is needed if module used during boot is changed.
Ubuntu Release Upgrade
1
2
| apt install update-manager-core
do-release-upgrade -d
|
Netplan
Apply netplan changes. Will not apply if there is syntax error in configuration files:
Try, will apply and auto revert:
Purge Uninstalled Packages
1
| apt-get purge $(dpkg -l | grep '^rc' | awk '{print $2}')
|
APT Cache
On apt cache server:
1
| apt install apt-cacher-ng
|
On other server:
1
| echo 'Acquire::http::Proxy "http://<cache-server>:3142";' > /etc/apt/apt.conf.d/00proxy
|
John Siu
Update: 2022-05-12
